Distraction Osteogenesis has been used in the facial skeleton following the principles laid down by Codvilla in 1905 and Ilizarov in 1952. McCarthy first introduced distraction osteogenesis in the mandible (lower jaw). Several distraction devices have been disclosed in the art.
McCarthy discloses in “Distraction of the craniofacial skeleton” (Springer Verlag, pages 68, 88, and 89; 1999) three extra-oral horizontal uniplanar and multiplanar distractors. The uniplanar distractors have two pin clamps, a distraction screw, and four percutaneous pins. The pins are of fixed length and about 80 mm long of which about 20 mm is fixed into the bone and 60 mm extends out of the bone. The diameter of the pin is between 10–15 mm in diameter. The distractor is placed percutaneously (through the skin of the face). The device is large, has a complex screw, and requires fixation through the skin with long pins. Therefore, fixation and removal needs to be performed under general anesthesia. McCarthy further describes two general drawings of intra-oral horizontal uniplanar distractors on page 98 and 99. On page 223, McCarthy discloses FIGS. 7.4 and 7.5 with two bulky intra-oral distractors with two guiding rails. FIG. 7.4 discloses a device with a distraction screw of about 3 cm long and a diameter larger than about 5 mm. The uniplanar distractor has two translating brackets, moving in opposite directions and no fixed bracket. All pieces are welded or soldered together. The device is large and complex and requires transmucosal fixation. FIG. 7.5 discloses a distraction screw of about 40 mm long and a diameter of about 6 mm The right fixed bracket is about 25 mm long, about 40 mm wide and about 8 mm thick. The left, translating bracket is about 40 m wide. The prominent interconnecting bars are positioned on top of the guiding rails. All pieces are welded or soldered together. The device is large and complex and requires transmucosal fixation
Unidirectional distraction devices with the numbers 51-500-10, 51-500-15 and 51-500-20 by Martin, comprise each 2 guiding rails, a fixed bracket, a translating bracket, 1 distraction screw, 6 osteosynthesis pins and 1 or more cranks. The distractor requires an interconnecting bar between the guiding rails. This distractor is large and requires a complex surgical operation for fixation and removal under general anesthesia.
Dyna Form is marketed and is an intraoral distraction system for widening of the jaw. It consists of a translating bracket with a cylinder, a distraction screw, a fixed bracket that extends above the translating bracket, two guiding rails, and pins. The distraction screw pushes against the extension of the fixed bracket. Size and construction of the device make it too bulky to be used in vertical alveolar distraction.
Jaw lengthening distraction devices with numbers 51-525-06, 51-525-09, 51-525-12 and 51-525-15 by Martin, each comprises a fixed bracket with up to 14 perforations, a translating bracket with a cylinder and up to 10 perforations, and 1 chamber. The chamber is partially hollow and contains the entire length of a distraction screw, except for the head. The chamber contains the cylinder of the translating bracket. The use of many lateral pins could lead to damage to adjacent anatomical structures. The use of a lengthy and bulky chamber with cylinder may be uncomfortable during the period of distraction and are too large for use in vertical alveolar distraction. Further, it seems that the distraction screw cannot be replaced with an alternative distraction screw without removal of one or more of the brackets. Similar devices have been described in DE 297 16 635 and are marketed by Synthes.
A vertical alveolar distractor by Stryker Leibinger comprises a translating bracket, a fixed bracket, 10 to 20 perforations in total, and one distraction screw and was presented at a conference in Paris, in June 1999. One perforation in the translating bracket is used as a cylinder for the distraction screw. The brackets are relatively thick. Some of the perforations are positioned in the distraction gap and interfere with the neo-osteogenic site. The use of many lateral pins could lead to damage to adjacent anatomical structures.
U.S. Pat. No. 5,769,850 (Chin) describes a device for vertical alveolar distraction osteogenesis containing a translating upper bracket with a cylinder, a fixed bracket with a chamber, a distraction screw, and pins. The distraction screw has one or more sharp ends. It is required to drill a hole in the bone to allow for rotation of the screw end within the 3 osseous segments. The device has sharp edges, does not have a smooth surface and extends into the osteogenesis site. The pins are screwed through the bracket towards the distraction screw. The device does not have a guiding rail and has a chamber, which is short in length. Similar devices are sold under the Lead System trademark name.
JP 10043203 (Keisei Ika) describes 2 types of devices: one device with a connection between the jaw and the cranium for extending the jaw away from the cranium and another device with two connections to the jaw for lengthening the ascending ramus of the mandible (=lower jaw). The devices contain a translating bracket (plate) with a cylinder, a fixed bracket with a chamber with an aperture (hole), and a distraction screw. The device extends (distracts) the ascending ramus of the mandible away from the cranium, uses pins and has a thin chamber. Devices use extensions into the site of osteogenesis. The devices have sharp edges, particularly the end of the screw and the brackets, and do not have a smooth surface. The prominent and sharp edges of the plate face away from the underlying jaw bone towards and into the soft tissues. Devices have extensions into the site of osteogenesis. None of the devices has a guiding rail. Devices are large with sizes of up to 100 mm and more, which is too large to be used for vertical alveolar distraction. Further, the pins are not threaded.
U.S. Pat. No. 5,895,387 (Guerrero) describes a distraction device for lengthening the jaw and for extending the cranium. The device has a translating bracket with a cylinder, a fixed bracket, and pins. However, the device has a large size and is not described for vertical alveolar distraction. Guerrero uses an anvil area and does not have an aperture in the chamber. The device does not have a guiding rail. The device has sharp edges instead of a smooth surface. In fact, it has “clamps” that extend into the site of osteogenesis.
U.S. Pat. No. 5,980,252 (Samchukov) describes a tooth borne alveolar distraction device containing a translating bracket with cylinder, a distraction screw, and a fixed bracket. The device does not have pins and does not have a guiding rail. The device has sharp edges and extensions into the site of osteogenesis. The distraction screw does not push against the chamber and the screw cannot easily be replaced during the distraction.
DE 298 13 087 (Karl Leibinger) describes a distraction device containing a translating bracket with a cylinder, a distraction screw, a fixed bracket and pins. The device has 2 guiding rails on the side of the screw to add to the stability while extending the length of the jaw. However, the fixed bracket does not have an aperture and the device seems too bulky for vertical alveolar distraction.
Surprisingly, we have found that one or more problems of the distractors of the prior art can be overcome by using the distractor device of the present invention.